A transsexual business executive claiming damages of £500,000 for discrimination at work has been ordered to leave the country by the Home Office.

Jessica Bussert, 41, has been told her work permit is no longer valid and she must return to the United States this week.

The senior IT consultant has claimed damages from Hitachi Data Systems at an employment tribunal for discrimination in what could prove a test case for transsexuals everywhere. But after she filed a claim for constructive dismissal she received a letter from the Home Office saying her work permit was no longer valid and she had 28 days to leave the country.

Ms Bussert, who claims she was "demoted" at work after having facial feminisation and breast surgery, believes her legal right to have her grievance heard in a tribunal has been flouted.

Her case has been taken up by transsexual rights groups and MPs who say her treatment is "outrageous."

Christine Burns, of Press for Change, said: "Jessica came to the UK expecting fairer treatment than in the USA. Instead it seems she faced discrimination the moment her transsexual status was known. Now, as a nation, we're adding insult to injury by booting her out before she can obtain redress. It's outrageous - but wholly in keeping with a government that continues to drag its heels to finish levelling the field for us."

The immigration minister, Liam Byrne, has been contacted by MPs asking for Ms Bussert to be allowed to stay in the country until her case has been heard by the tribunal, which will begin in November.

Ms Bussert, whose wife Sharon will also have to leave the country this week, said she would continue to fight her case and would fly back to Britain from Indiana.

Said Ms Bussert: "I expected a bit more from this great nation. Sharon and I had hoped to make England our long-term home. We left the US to seek the tolerance and protections offered by British society. After all of this, it makes you wonder just how tolerant the Home Office really is."